Firewall Builder 4.0 is currently in beta testing phase. If you find it interesting after reading this post, please download and try it out. Source code archives, binary deb and rpm packages for popular Linux distributions and commercially distributed Windows and Mac OS X packages are available for download here.

In this post I demonstrate how Firewall Builder can be used to generate firewall configuration for a clustered web server with multiple virtual IP addresses. The firewall is running on each web server in the cluster. This example assumes the cluster is built with heartbeat using “old” style configuration files, but which high availability software is used to build the cluster is not really essential. I start with the setup that consists of two identical servers running Linux but in the end of the article I am going to demonstrate how this configuration can be converted to OpenBSD with CARP.[click to continue…]

Lets see how much effort it is going to take to convert this configuration to entirely different firewall platform – PF on OpenBSD. There are different ways to do this. I could make a copy of each member firewall (linux-test-1 and linux-test-2), set platform and host OS in the copy to PF and OpenBSD and then create new cluster object. This would be a sensible way because it preserves old objects which helps to roll back in case something does not work out. However, to make the explanation shorter, I am going to make the changes in place by modifying existing objects.[click to continue…]